Iodide accumulation provides kelp with an inorganic antioxidant impacting atmospheric chemistry.
Kupper, Frithjof C.; Carpenter, Lucy J.; McFiggans, Gordon B.; Palmer, Carl J.; Waite, Tim J.; Boneberg, Eva-Maria; Woitsch, Sonja; Weiller, Markus; Abela, Rafael; Grolimund, Daniel; Potin, Philippe; Butler, Alison; Luther, George W., III; Kroneck, Peter M. H.; Meyer-Klaucke, Wolfram; Feiters, Martin C.
Dunstaffnage Marine Laboratory, Scottish Association for Marine Science, Argyll, UK. Proceedings of the National Academy of Sciences of the United States of America (2008), 105(19), 6954-6958. Publisher: National Academy of Sciences,
Abstract
Brown algae of the Laminariales (kelps) are the strongest accumulators of iodine among living organisms. They represent a major pump in the global biogeochem. cycle of iodine and, in particular, the major source of iodocarbons in the coastal atm. Nevertheless, the chem. state and biol. significance of accumulated iodine have remained unknown to this date. Using x-ray absorption spectroscopy, we show that the accumulated form is iodide, which readily scavenges a variety of reactive oxygen species (ROS). We propose here that its biol. role is that of an inorg. antioxidant, the first to be described in a living system. Upon oxidative stress, iodide is effluxed. On the thallus surface and in the apoplast, iodide detoxifies both aq. oxidants and ozone, the latter resulting in the release of high levels of mol. iodine and the consequent formation of hygroscopic iodine oxides leading to particles, which are precursors to cloud condensation nuclei. In a complementary set of expts. using a heterologous system, iodide was found to effectively scavenge ROS in human blood cells.
Kupper, Frithjof C.; Carpenter, Lucy J.; McFiggans, Gordon B.; Palmer, Carl J.; Waite, Tim J.; Boneberg, Eva-Maria; Woitsch, Sonja; Weiller, Markus; Abela, Rafael; Grolimund, Daniel; Potin, Philippe; Butler, Alison; Luther, George W., III; Kroneck, Peter M. H.; Meyer-Klaucke, Wolfram; Feiters, Martin C.
Dunstaffnage Marine Laboratory, Scottish Association for Marine Science, Argyll, UK. Proceedings of the National Academy of Sciences of the United States of America (2008), 105(19), 6954-6958. Publisher: National Academy of Sciences,
Abstract
Brown algae of the Laminariales (kelps) are the strongest accumulators of iodine among living organisms. They represent a major pump in the global biogeochem. cycle of iodine and, in particular, the major source of iodocarbons in the coastal atm. Nevertheless, the chem. state and biol. significance of accumulated iodine have remained unknown to this date. Using x-ray absorption spectroscopy, we show that the accumulated form is iodide, which readily scavenges a variety of reactive oxygen species (ROS). We propose here that its biol. role is that of an inorg. antioxidant, the first to be described in a living system. Upon oxidative stress, iodide is effluxed. On the thallus surface and in the apoplast, iodide detoxifies both aq. oxidants and ozone, the latter resulting in the release of high levels of mol. iodine and the consequent formation of hygroscopic iodine oxides leading to particles, which are precursors to cloud condensation nuclei. In a complementary set of expts. using a heterologous system, iodide was found to effectively scavenge ROS in human blood cells.
